In recent years, a higher efficiency and a higher productivity have been demanded for the processing of color photographic light-sensitive materials. This tendency is remarkable particularly for the production of color prints. In order to meet the demand for early delivery and win the price race, so-called color laboratories have been integrated into large-scale laboratories with a higher production efficiency or decentralized to small-scale laboratories that can meet the demand for early delivery. The two types of laboratories are opposite in form. However, the two types of laboratories are the same in that they have a strong demand for a higher printing yield. Since it has recently become difficult to train skilled operators, the stability of the properties of color print light-sensitive materials (hereinafter referred to as "color photographic material") to be used is an important factor that affects the printing yield. In particular, when the photographic properties fluctuate between lots of production of color photographic papers or during the storage of color photographic papers in the laboratories, the printing conditions have to be reset. Thus, high efficiency cannot be attained in the production.
On the other hand, the inventors have found that the temperature fluctuation upon exposure is another great factor that causes a fluctuation in the properties of color photographic papers. When the sensitivity or other properties fluctuate due to the temperature fluctuation upon exposure, it causes trouble. For example, when the temperature upon exposure rises due to heat from a lamp or the like during printing, the print density or color balance changes if the printing conditions are left set at the initial values, making it impossible to obtain excellent prints. Therefore, a high production efficiency cannot be obtained with light-sensitive materials having a great temperature dependence upon exposure.
Besides, the stability of the photographic properties, the shortening of print processing time has been desired to meet the demand for early delivery.
In order to speed up development processing, silver bromide, silver bromochloride and silver chloride emulsions substantially free of silver iodide have been used as silver halide emulsions to be incorporated in color photographic papers. It has been known that the higher the silver chloride content is of a silver halide emulsion, the higher is the development rate and the more advantageous it becomes in rapid processing. However, it has also been known that the higher the silver chloride content is, the easier the silver halide emulsion is subjected to fog and the harder it is to obtain a high sensitivity. It has been reported that various compounds called photographic stabilizers can be effectively used to eliminate these disadvantages. In particular, JP-A-62-269957 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") corresponding to European Patent 0,246,624 describes that the mercapto compounds represented by the general formula (II), (III) or (IV) disclosed later in the present specification can be advantageously used to improve the effect of inhibiting fog of a silver halide emulsion having a high silver halide content.
On the other hand, it also has been known that as the silver chloride content increases, the adsorptivity of a spectral sensitizing dye decreases. This is another factor that accelerates the fluctuation in properties during the preparation or storage of color photographic papers. In particular, a pentamethine-cyanine dye commonly used for the purpose of spectrally sensitizing color photographic papers in the red light region is disadvantageous in that the adsorptivity of a coating solution prepared in the production fluctuates with time, resulting in a change of photographic sensitivity or in fluctuation in the sensitivity during extended storage. It has been made clear that the mercapto compounds of the general formula (II), (III) or (IV) accelerate the sensitivity change (particularly desensitization) due to ageing of the coating solution.
Processes have already been known for reducing the sensitivity fluctuation due to ageing of a coating solution comprising a red-sensitive spectral sensitizing dye. For example, examples of spectral sensitizing dyes which are insasceptible to a drop in sensitivity with time are disclosed in JP-A-59-166955. However it has been made clear that even these spectral sensitizing dyes leave much to be desired. In particular, when a mercapto compound such as that of the general formula (II), (III) or (IV) of the present invention is used, these spectral sensitizing dyes cannot sufficiently exhibit their effects. In addition, it has also been made clear that these spectral sensitizing dyes leave much to be desired in the reduction of the sensitivity fluctuation during the storage of the products or the sensitivity change with the temperature change upon exposure. It has further been made clear that these disadvantages become more remarkable as the silver chloride content of the silver halide emulsion increases.
Furthermore, U.S. Pat. No. 4,513,081 discloses another spectral sensitizing dye which can reduce desensitization caused by the ageing of a coating solution. However, this dye, too, leaves much to be desired in the reduction in the sensitivity change during the storage of the product or due to the temperature change upon exposure.
The inventors made a study to overcome these problems. As a result, the inventors found a group of compounds represented by the general formula (I), described later, as spectral sensitizing dyes which are excellent in their stability of the coating solution with time and their stability of the photographic properties during storage of the product and which are less subject to temperature dependence upon exposure. However, as a result of a practical test on a light-sensitive material comprising these sensitizing dyes, it has been made clear that these spectral sensitizing dyes have a serious problem. In particular, the edge portion produced by cutting of the light-sensitive material colors undesirably upon development. Such an undesirable coloring drastically impairs the quality of color prints particularly with a white edge. Such a product cannot be offered to the market.
It has therefore been keenly desired to provide a silver halide photographic material which is suited to improve the productivity of color prints, capable of being processed rapidly, and excellent in stability of photographic properties and edge whiteness.